Mammal. The capybara is the largest of all living rodents. In the language of the Guarani Indians, capybara means “master of the grasses.” Capybaras live close to the water in groups of about 20. They are excellent swimmers and divers. If they sense danger, they will dive into the water and hide, and they can stay underwater for five minutes. If necessary they can even sleep underwater with only their noses poking out. Capybaras communicate with a variety of sounds including soft whimpers, clicking noises, purring and barking. All females within the group help care for and nurse the young.